SQL Pass Through
You can mix NDO queries and Save() calls with pure SQL Statements. You can use a SqlPassThroughHandler for this purpose:
var handler = persistenceManager.GetSqlPassThroughHandler();
handler.BeginTransaction(); // if needed
handler.Execute( yourSqlStatementsAsString );
handler.CommitTransaction(); // you can omit this call and call Save() instead to include
// operations on objects into the transaction